Integration test for network parameter updates and improved logging (#2863)

node-api/src/main/kotlin/net/corda/nodeapi/internal/network/NetworkMap.kt

@@ -31,7 +31,14 @@ data class NetworkMap(
         val nodeInfoHashes: List<SecureHash>,
         val networkParameterHash: SecureHash,
         val parametersUpdate: ParametersUpdate?
-)
+) {
+    override fun toString(): String {
+        return """${NetworkMap::class.java.simpleName}(nodeInfoHashes=
+${nodeInfoHashes.joinToString("\n")}
+networkParameterHash=$networkParameterHash
+parametersUpdate=$parametersUpdate)"""
+    }
+}
 
 /**
  * Data class representing scheduled network parameters update.